Travelling gantry for operating aluminum electrolysis furnaces



March is, 1969 J. N. STROM Em. 3,433,879

TRAVELLING GANTRY FOR OPERATING ALUMINUM ELECTROLYSIS FURNACES FiledMarch 24, 1967 INVEA'I'TOIZSZ u. /v. STEO/H G. HEGGST/JD flazw, MW

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DRNE M3 MOTOR wvEymzsj: J.N. 3720M wees-m0 5 v 'dfmd #1004 United StatesPatent 3,433,879 TRAVELLING GANTRY FOR OPERATING ALUMINUM ELECTROLYSISFURNACES Johan Nikolai Strtim and Gudmund Heggstad, Hoyanger, Norway,assignors to A/ S Norsk Aluminum Company, Oslo, Norway, a corporation ofNorway Continuation-impart of application Ser. No. 348,521, Mar. 2,1964. This application Mar. 24, 1967, Ser. No. 625,695 Claims priority,application Norway, Mar. 4, 1963, 147 755 US. CI. 13-33 5 Claims Int.Cl. H051) 3/60 ABSTRACT OF THE DISCLOSURE This application is acontinuation-in-part of an application entitled, Means for OperatingAluminum Electrolysis Furnaces, Including Crust Breaking and OxideCharging, Ser. No. 348,521, filed Mar. 2, 1964, now abandoned.

The present invention relates to electrolytic cells or furnaces and,more particularly to apparatus for automatic feeding of the cells.

In the operation of aluminum electrolysis furnaces, it has becomeconventional, for the breaking of furnace crusts and the charging ofoxide and other materials required for the running of the furnace, touse automated mechanical equipment in lieu of the prior manualoperations of breaking the crust by sledge and/ or crowbar and chargingby spade and hand car. In this manner, it has been possible toadvantageously reduce the need of manpower, since a single man mayoperate the entire equipment, both for the crust breaking and the oxidecharging and any other necessary operation. However, such mechanicalequipment is quite heavy so that it has been found to be necessary tomount the same in special cars or travelling crabs that move along thefurnace. Also, it has been found that a necessary requirement is toprovide for protection of the operator of such equipment, both againstthe heat from the furnaces and against escaping gases.

Thus, one object of the present invention is to provide means which toan even higher degree than before reduces the need of manual labor andgreatly simplifies the equipment and the supporting structure.

It is another object of the present invention to eliminate the need forcomplicated and expensive safety devices to protect the operator sincethe entire operating means of the present invention may be operated froma remote point in the building, at a good distance from the furnacesthemselves.

In accordance with the invention, there is provided a gantry orportal-like framework which is movable longitudinally along the furnaceor furnaces and which, on at least one transverse side thereof, carriesan oxide charging silo and a crust breaking device. One important andcharacteristic feature of the apparatus of the invention is theprovision of electric contact means adapted to cooperate 3,433,879Patented Mar. 18, 1969 with stationary stops at the ends of theindividual furnaces for operating a master control circuit which, inturn, automatically controls the movements of the gantry framework, theoperation of the crust breaking device and the outlet valve of the oxidecharging silo. In addition, auxiliary wheels are provided on theframework for shifting the furnace operating means from one furnace toanother in response to the master control circuit and along a pathtransverse to the furnaces themselves. As a result, when the apparatusof the present invention is utilized, the operator does not have toaccompany the equipment during the operation on each individual furnaceor during the shifting operation from one furnace to the other.Furthermore, the gantry framework provides the operating means withimproved stability so that the heavy equipment is always assuming acorrect position relative to the furnace being treated. It is also anadvantage of the gantry framework of the present invention that theequipment, which is not only very heavy, but also subjected to intensivedynamic and/ or sidewise strains under operation, is rigidly mountedalong the depending legs of the framework so as to be supported near tothe floor of the building.

The importance of the auxiliary wheels for moving the entire furnaceoperating equipment from one furnace to the next lies in the fact thatthis reduces the number of units in a particular building to a minimum.Specifically, in accordance with this feature, the framework is providedwith auxiliary wheels adapted to be raised and lowered into and out ofengagement with the floor and having a direction of movement transverseto the longitudinal direction of the furnaces. The arrangement is suchthat the ordinary travelling wheels for the movement of the frameworkalong the furnace during the feeding operation are raised clear of theirrespective rails when the auxiliary wheels are in operative positionagainst the floor.

To provide power to the individual driving motors for the wheels of theframework and the operation of the crust breaking and oxide chargingequipment, the gantry framework may be provided with a selectivelyrotatable trolley or boom carrying contact pieces adapted to cooperatewith contact rails extending longitudinally along the furnace orfurnaces. In this manner, no cable conductors to the equipment areneeded, so that the floor remains free of these obstructions and thepossibility of damage to the cables is avoided, which has been a problemin the past.

In the drawings:

FIGURE 1 shows an operating unit constructed in accordance with thepresent invention as seen longitudinally of an electrolysis furnace; allparts which are not essential to the understanding of the invention,such as the crust breaking equipment and the furnace proper, being inpart deleted and in part shown strictly schematically;

FIGURE 1a is a view taken along line 1a-1a of FIG- URE l; and

FIGURE 2 is a schematic diagram of the control system for the operatingunit of FIGURE 1 showing the manner in which the several parts andelements are interrelated in accordance with the invention.

As shown in FIGURE 1 of the drawings, the operating unit comprises alattice framework I mounted on a suitable number of bogies 2, eachprovided with a wheel 2a and a gear motor 3 for driving at least one ofsaid wheels 2a for effecting movement of the unit along furnace or cellF and from one operating location to another as required. The motors 3are reversible so that the unit may be run in either direction along thefurnace F. In the upper part of the preferred embodiment of the unit,each leg L is provided with an oxide silo 4 having a filling opening 4afor charging the furnace F in a manner to be discussed later. Theframework 1 also carries a power transfer arm 5 which is pivotable aboutthe vertical axis by a turntable 6 and also pivotable about a horizontalaxis at a pivot pin 7. The turning in the horizontal plane may beeffected by means of a motor 8 connected to the turntable 6, while thevertical positioning about the pin 7 is effected under the control of ahydraulic cylinder 9. Electric current collectors 11 are arranged at thefree end of the arm so as to be adapted to cooperate with power rails 12extending along the furnace F; the power rails 12 being suspended from awall W of the building, if desired.

The crust breaker does not constitute any part of the present invention,and is thereby merely schematically indicated at at-the lower part ofthe legs L of the framework 1. As is conventional, tools 10a extenddownwardly into engagement with or in juxtaposition to the crust on thesurface of the molten metal in the furnace F for performing the usualcrust breaking function.

At the lower end of the charging silos 4, there is provided aconventional electrically operated valve 13 from which two tubes .14,14a (see FIGURE 1a) are extending downwardly towards the furnace so asto deliver charging oxide to the furnace F. The tubes 14 open justadjacent to opposite sides of the crust breaking tool 101:; only onesuch tube 14, 14a being in operation at a time, that is the one whichhas its outlet opening behind the crust breaking tool in the directionof movement of the unit. The arrangement allows the oxide from theoperative tube 14, 14a to be always caused to flow into the opening inthe furnace crust provided by the tool 10a that precedes it along thefurnace F.

A transversely running wheel 15 is arranged in connection with eachibogie 2 (the near two being viewable in FIGURE 1); such wheels 15 beingmounted on pivotal levers 15a so as to be adapted to be positioned inthe raised position during usual operation along the furnace F, asshown, but adapted to be lowered by means of a hydraulic cylinder 16 tothereby raise the entire framework 1 whereby the ordinary running wheels2a in the bogies 2 are cleared from their rails and the framework may beshifted transversely of the furnace F to a new furnace F, for example.

The framework 1 carries limit contact switches 18, 19 adapted tocooperate with fixed sensor arms of stoppers 18a, 19a mounted onopposite ends of the furnace F; as shown in FIGURE 1, for a purpose ofcontrolling the operation of the unit, as will now be explained.

Thus, with specific reference to FIGURE 2 of the drawings, assuming thatthe initial position of the unit is at one end of the furnace F, a mainswitch 20 is manually operated to connect the rails 12 to the main powersupply 21 to initiate the overall operation of the unit. Master controlcircuit 22 thus receives power through the turntable 6 for initiatingthe movement of the unit along the furnace F to perform the crustbreaking, charging and shifting operations in proper sequence asdesired. It should be pointed out that the control circuit 22 itselfdoes not per se form any part of the present invention and may be anyone of a number of conventional devices, such as for example, aconventional rotary wiper selector that is stepped around in a circle toactuate a plurality of individual switches to bring about successiveoperations in timed sequence; it being understood that other electronicswitching circuits and computers may be employed if desired.

The circuit 22 is arranged to first initiate the operation of the crustbreaker 110 as soon as the main switch 20 is closed. The reversibledrive motor 3 is connected to the control circuit 22 through aconventional start delay relay 25 so that it can be started next with acertain time delay selected to correspond to the time required for thecrust breaking tool 10a to initially break through the crust. Similarly,the silo valve 13 for operating the proper tube 14, 14a that followsdirectly behind the tool 10a is operated through a second start delayrelay 2 6 so that the charging operation takes place only after the unithas moved a short distance along the furnace F and the crust has beenbroken. If desired, as an additional safety feature, the relay 26 may beprovided with an interlock switch 27 positioned so as to directly sensethe presence of an opening in the crust before allowing the completionof the circuit to open the valve 13.

After the time of the delays 25, 26 has elapsed, the unit advances alongthe furnace F with the crust breaker 10 breaking a lane in the crust andthe charge being fed from the silo 4 until the unit reaches the end ofthe furnace F. At this point, the appropriate switch 18, 19 strikes itscorresponding arm 18a, 19a whereby the control circuit terminates theoperation of the motor 3 and the crust breaker 10 and operates the valve13 to terminate the flow of oxide from the tube 14, 14a.

In order to be able to move the unit over to the next furnace row whenthe operation on the furnace F is complete, the master control circuit22 next operates a hydraulic valve 30 which is connected to actuate thehydraulic cylinder 16 by introduction of fluid from hydraulic powersource 31 whereby the wheels 15 are lowered and the entire unit israised. At the same time, the valve 30 may be connected to actuate thecylinder 9 whereby the arm 5 (FIGURE 1) is automatically lowered so thatthe current collectors 11 are released from the power rails 12. One ofthe wheels 15 is driven during the transverse run by a separate motor 32from a separate power source 33 which may take the form of a movableconductor provided with a plug and cooperating with an electrical outletin the wall W.

If the current rails 12 of the next furnace row are positioned on theopposite wall from the illustrated wall W, the arm 5 may be turned inthe horizontal plane by actuation of ahe motor 8 during this transversemovement on the wheels 15.

In this disclosure, there is shown and described only the preferredembodiment of the invention, but, as aforementioned, it is to beunderstood that the invention is capable of various changes ormodifications within the scope of the inventive concept as expressed bythe accompanying claims. Obviously, the unit of the invention may, forexample, be provided with security means, instruments and furtherequipment which might be desired due to local considerations. In anycase, it will be realized that the travelling gantry unit of the presentinvention affords an extremely efficient and simplified means by whichthe charging operation may be automatically performed in a continuousfashion along either a single furnace F or along a plurality of furnacesF, F in succession, if desired.

We claim:

1. An apparatus for operating an elongated aluminum electrolysis furnacepositioned along a floor having a body of molten aluminum upon whichcrust breaking and oxide charging operations are to be performed,comprising a gantry framework for spanning the furnaces, said frameworkbeing movable longitudinally along said furnace, a silo for chargingmaterial mounted on said framework along a leg of said frameworkadjacent the side of said furnace, said silo being provided with outletmeans having a discharge opening adjacent the crust formed on thealuminum in said furnace, a valve for controlling the flow of chargingmaterial from said outlet means into said furnace, a crust breakingdevice on said framework in juxtaposition with said silo for operationon the crust formed on said body adjacent said outlet opening, electricswitch means on said framework, first and second stationary stop meansprovided at opposite end of said furnace for operating said switchmeans, drive means on said framework for engagement with said floor tomove the same along said furnace, and control means for operating saiddrive means, said crust breaking device and said valve in propersequence, said switch means being connected to said control means toterminate the operation of said drive means, said crust breaking deviceand said valve at the ends of said furnace whereby said operations areperformed along the full length of the furnace.

2. An apparatus as claimed in claim 1, wherein said gantry framework isprovided with auxiliary means for raising said drive means free of saidfloor and for causing shifting movement of said apparatus transverselyof said furnace to allow placement of the same in position spacedtransversely from said furnace.

3. An apparatus as claimed in claim 1, wherein is further provided powerrails extending along at least one side of said furnace, said gantryframework being provided with a horizontal boom for supplying power tosaid apparatus from said power rails, a turntable for mounting said boomfor adjustable movement about a vertical axis, and motor means foroperating said turntable, whereby said boom is adapted for cooperationwith said power rails extending longitudinally of the furnaces on eitherside thereof.

4. An apparatus as claimed in claim 1, wherein is further providedhorizontal pivot means on said boom, and power means for operating thefree end of said boom whereby said boom may be lowered away from saidpower rails.

5. An apparatus as claimed in claim 2 wherein said auxiliary meanscomprises a plurality of wheels on said framework, said wheels beingmounted on pivotal arms having a horizontal pivot axis, power meansconnected to said arms for movement of said wheels toward and away fromsaid floor.

References Cited UNITED STATES PATENTS 2,827,182 3/1958 Grifiin et a1.214l8 2,928,658 3/ 1960 Killebrew. 2,964,305 12/1960 Samhammer et al.3,186,927 6/ 1965 Montovanello 20467 3,216,595 11/1965 Wethly 21418BERNARD A. GILHEANY, Primary Examiner.

ROY N. ENVALL, JR., Assistant Examiner.

US. Cl. X.R.

